Acetobromomaltose, a New Source of Carbohydrate Radicals. EPR Characterisation of Maltosyl and 2-Deoxymaltos-2-yl Radicals and Syntheses of Tetrasaccharide-like Mimics, Maltal, 3-α-Maltosyl Propiononitrile, 1,5-Anhydromaltitol and 2-Deoxymaltopyranoside
作者:Angelo Alberti、Sabrina Bertini、Maura Comoli、Marco Guerrini、Andrea Mele、Elena Vismara
DOI:10.1016/s0040-4020(00)00567-6
日期:2000.8
detected, resulting from migration of an acetoxy group from position 2 to position 1. Some acetoxy-protected maltose derivatives were prepared from ABM, via different radical pathways involving 1 and 2 as intermediates. Electroreduction on silver provides tetrasaccharide-like mimics 7 and maltal 8. Photochemical generation of 1, followed by trapping with tributyltinhydride or with acrylonitrile, leads
通过EPR光谱研究了通过从乙酰溴代麦芽糖(ABM)中提取溴而得到的乙酰氧基保护的麦芽糖基基团1。在室温下,仅观察到光谱1,但在较高温度下,检测到第二个自由基,即乙酰氧基保护的2-deoxymaltos-2-yl自由基2,其原因是乙酰氧基从位置2迁移到位置1由ABM通过涉及1和2作为中间体的不同自由基途径制备了一些乙酰氧基保护的麦芽糖衍生物。银上的电还原提供了类似四糖的模拟物7和maltal 8。光化学生成1,然后用三丁基氢化锡或丙烯腈捕集,分别导致1,5-脱水麦芽糖醇9和3-α-麦芽糖基丙腈10。在80°C下通过1 → 2异构化生成2,然后用三丁基锡氢化物捕集,生成2-脱氧麦芽吡喃糖苷11。